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Find the number of terms of the AP -12,-9,-6...,21. If 1 is added to each term of this AP then find the sum of all terms of the AP thus obtained
Answers
Answered by
0
Answer:
We have; n = 22, d = 7 and a22 = 149
We know;
a
n
=
a
+
(
n
–
1
)
d
Or,
149
=
a
+
21
×
7
Or,
a
=
149
–
147
=
2
The sum can be calculated as follows:
S
=
n
2
[
2
a
+
(
n
−
1
)
d
]
=
22
2
(
2
+
149
)
=
11
×
151
=
1661
Step-by-step explanation:
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Answered by
0
Answer:
n = 32
Step-by-step explanation:
first term = -12
common difference = -12-(-9) = -4
nth term = 21
nth term = a + (n-1)d
21 = -12 +(n-1)-4
21= -12 -4n+4
21+12-4/4= n
32 = n
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